Recently, I visited with my friends Walter Bender and Jim Gettys at the new headquarters of the One Laptop per Child Project. I'm writing an article for the IEEE Spectrum on the project and had asked Walter if I could come by and grill him on the technical and conceptual details of the project. But thats really just an excuse - I'm fascinated by the project, and am trying to offer what help I can to Nicholas Negroponte and his team in helping people understand what the project is and isn't, offering my perspective on how the device might best be rolled out, supported and used in developing nations.

One of the most interesting phenomena surrounding the One Laptop Per Child project has been the amount of attention its garnered, not just from the development community, but from average users around the world. Interest in the project seems to focus on a basic and very compelling idea: a laptop that costs a hundred dollars or less. After writing my earlier piece on OLPC, I now average 20 emails a week asking to purchase the laptop, or receive one as a gift. I now have a keyboard macro that gives a stock response: I'm not officially affiliated with the project, the laptop isn't available yet, and when it is, it will be sold in lots of a million or more to governments and school systems.

Most of the people who write me are interested in owning a laptop they can afford. And that, it turns out, is not the goal of the One Laptop Per Child project. Their goal is to produce a laptop designed for use by children - students in grades K-12. And that requires radically different design decisions than what one would make in simply creating a low-cost laptop.

Getting across the distinction that this is a childrens laptop, not just a cheap laptop, is a surprisingly difficult task. When I last wrote about the laptop on Worldchanging, a number of commenters mentioned that theyd like one of the computers as a backup or travel computer - I suspect they might feel differently after playing with one of the current prototypes. Theyre really small. This is a good thing - I wouldn't want a kindergarten student carrying around my 12" PowerBook - its too heavy and too fragile. The current prototype is little, orange, and very, very cute. It has a molded plastic handle and looks remarkably like a Speak and Spell.

It's got bunny ears - antenni for the 802.11s wireless radios, which are designed to self-assemble meshes with other laptops. The ears fold down to cover the USB, power and mic ports, an excellent design for the sorts of dusty environments I can imagine the device used in. The screen in the current prototype is a conventional LCD screen - the screen in the production devices will be roughly the same size, probably slightly larger than the 7.5" screen in the prototype, but will be based around a technique that doesnt require white fluorescent backlight. (Many of the questions I need to answer for the IEEE article concern the screen, as its one of the most expensive and power-hungry components of the machine.) The keyboard is about 60% of the size of a conventional keyboard and has calculator-style keys.

My favorite feature of the current prototype is the hinge that holds the machine together. Ever since Nicholas outlined the engineering challenges of building a good hinge, I've been fascinated by the different ways people attach screens to laptops. As promised, the laptop can be folded into an ebook, with the screen on top, used as a handheld game player, or have the screen turned around so the machine can be used as a video player. Walter tells me that Quanta, the company responsible for manufacturing the machine, insisted on the hinge used in the prototype because its the only one they trusted to stand up to the wear kids will put on the machine.

In other words, while I love it, I'm not trading my laptop in for one any time soon. I suspect that low-cost computers designed by AMD and others are likely more appropriate for most users than the laptop. Again, thats okay - the goal isn't to capture the bottom end of the laptop market - it's to give kids learning tools. If the laptop did become popular on the low end of the market, it becomes a target for theft, which is one of the reasons the machine is a brilliant shade of orange.

The one feature missing from the prototype I saw - the crank. It's been clear - even before Kofi Annan broke the crank off an early laptop prototype - that a power-generating crank attached to the machine, like cranks are incorporated into FreePlay radios, might not work. Jim, who has designed the motherboard of the machine and has been focused on power consumption, helped me understand why.

Contrary to what you learned in The Matrix, human beings are lousy at generating electric power. Small children are capable of generating between five and ten watts, for short periods of time. Since conventional laptops draw about 6 to 8 watts with their screens turned on, thats a real problem for a child-powered laptop. The laptop needs to get much less power-hungry, and power generation needs to maximize the output a child is capable of. This means being ergonomically smart - use large muscle groups, and use human-generated motion efficiently. A crank attached to a laptop fails on both fronts - to crank a box, you fight the tendency of the laptop to move in the opposite direction of the crank. This means you either hold the laptop in one hand and crank with the other - and do work with both arms - or put the laptop on a table and run the good chance of it falling off a table. And cranks use small muscle groups - the triceps, hand and wrist muscles.

The solution is to make power generation an external add-on. The team is working on microgenerators that produce power using really big cranks - ones you might anchor with a hole in a table, and crank using your whole upper body. (Think Oompa Loompas in Wonkas chocolate factory opening valves.) Other microgenerators use a pullcord, the sort I use to start my lawnmower, or pedal power. And other power sources, including solar panels, could plug into the input jack of the machine. The current prototype accepts voltage from -23 to +23v, which lets power hackers be very creative - and more than a little sloppy - in providing power to the device. Got a power block for a laptop? If you can make the connector fit, it will power the laptop.

The prototype I saw didn't have a battery installed, but the team has decided to use nickel metal hybrid batteries rather than lithium ion. The rationale? Lithium is not very tolerant of voltage spikes - you need to regulate the power that enters the battery to prevent damage to it. Human-generated power is necessarily spiky, so regulating that voltage means losing generated power. NiMH is less efficient than Li-Ion in terms of power transfer, but the ability to capture spiky power is worth the trade-off and MnH batteries are somewhat easier to dispose of in an environmentally conscious manner than Li-Ion.

The machine still needs to be miserly with power to be usable as a human-charged device. And this is where the team have worked some serious magic. When the machine is not in active use, it can act as a mesh node, helping maintain a connectivity cloud over a village or school while drawing only 0.5 watts - the wireless subsystem (a Marvell chip with 100kb of RAM) operates independently of the main processor and can forward packets with the CPU shut down. The machine draws a similar amount of power in ebook mode, using a black and white display. The display IC has a substantial frame buffer - this means it can store a black and white image and display it without any assistance from the CPU, again allowing the CPU to shut down and save power. With the processor and color screen in action, the laptop draws 2 to 2.5 watts. To get the power consumption so low, Jim and the team chose an older AMD chip - the Geode GX2 - rather than the newer chips, which burn more power. Using the GX2 chip and the version of Fedora Red Hat has been developing for the machine, many Linux packages run on the laptop with almost no porting effort.

The board itself is designed to encourage hardware hacking - the 500 prototype boards currently built come with a VGA jack soldered on. But production models will leave the jack leads etched on the board, though unpopulated. Want to turn a laptop into a device that can drive an external monitor? Solder one on. Also on the board but unpopulated will be connectors for additional RAM and flash memory, as well as a mini-PCI slot. A goal for the next iteration is a board with a wider pitch, which makes it easier to repair the board or to hand-solder additional connections. The case is designed to be easy to open and access the innards - this makes it easier to make Frankenmachines from dead machines, and also makes it easier to mass produce lots of these devices quickly.

The storage capacity is decidedly modest - 128MB of RAM, 512MB of flash memory instead of a hard drive. That 512MB has to hold the operating system and applications, as well as any documents. No ones going to be loading a complete copy of Wikipedia onto this any time soon. That said, Walter showed me an early prototype of another orange box - a wire/wireless interface. Basically, its a wireless base station, designed to connect some of the laptop mesh nodes to an ethernet cable (presumably attached to a VSAT or some other device.) The box acts as a peer on the network, not a server, but has a larger storage capacity, so could serve as a document server as well as a web cacheing server. And you just might load Wikipedia -- or an edited, educational version of Wikipedia -- onto these boxes before distributing them.

The prototype running at the OLPC offices was running GNOME on top of Fedora, and looked very much like one expects a Linux desktop to look. This is not what most children will see when they turn on the machine, but its important to the designers that the machine be designed in layers, like an onion. (Or a parfait. Software designers like parfait.) For expert users who want to develop on the system, the laptop will ship with gcc, gtk, and the other stuff you need to build and distribute software. In addition, the software will include three development environments: Python, Javascript and Logowiki.

Logowiki, from what I've seen of it, is amazingly cool. It starts from a collection of wiki pages, like Wikipedia, and treats pages as computational objects. This means that the Wikipedia page on Logo would run Logo, letting you try out functions and move the turtle around. This opens up some amazing possibilities - wiki pages about physics that include programmable models that help you understand acceleration or momentum, for instance. And, indeed, you can come onto logowiki and play with little programs that build spirals or calculate Pi.

Wikis are important to the architecture of the software for another reason - theyre part of the subversive strategy behind the machine. The OLPC team wont have control over what content is loaded onto the laptop in different countries - thats the decision of individual education ministries. But by using wikis as a content management system - rather than, say, a PDF viewer - the team manages to sneak in the idea of user-generated content into schools. Perhaps most textbook pages will be protected in a wiki structure - wiki features like discussion pages will still exist, opening new possibilities for how kids interact with schoolbooks.

Walter explains that the fundamental design goals for the software of the project are to give students and teachers tools that leverage their ability to learn, their ability to be expressive and their ability to be social. A simple interface - more for discussion than a rough draft of any actual interface - shows some of these ideas. It's a tabbed interface, like a web browser, which holds applications like a word processor in some of the windows. Another window holds a graphical chat program, designed to let a student type or draw messages to another student - the chat is aware of what other students are logged on and proximate to the machine. The goal is not to isolate students from one another, having them stare into their machines, but to encourage them to communicate through the machines.